The overall objectives of this grant are: (1) To examine the interaction between the narcotics and agents which modulate activity along biochemically well-defined pathways in brain, particularly the catecholamine-containing pathways; (2) To examine the effects of acute and chronic narcotic administration on reproductive endocrinology in the rat; and (3) To develop a mass fragmentographic method for the detection of morphine in serum and brain which would permit an assessment of the pharmacodynamics of the narcotics, particularly with respect to their physiological disposition in brain.